Table 1. Characteristics of participants in the three examination areas.

	Aomori		Yamanashi		Nagasaki		All areas		Total
	(n = 1,630)		(n = 1,366)		(n = 1,369)
Age, y	Male	Female	Male	Female	Male	Female	Male	Female
3–4	11	14	1	4	21	20	33	38	71
5–9	181	173	148	170	210	210	539	553	1,092
10–14	352	321	295	305	295	295	942	921	1,863
15–18	239	339	154	289	168	150	561	778	1,339
Total	783	847	598	768	694	675	2,075	2,290	4,365